Wrap IRemoteTransition in a parcelable to enable extra properties

This is in preparation for attaching some extra meta information
to remote transitions (eg. process token). Most of this refactor
just replaces references to the raw interface with references
to the wrapper class.

There is also a small refactor in RemoteTransitionHandler to
better-manage death-recipients. It is possible to have >1 filter
and >1 pendings referencing the same remote simultaneously, so
this arrangement properly handles the 1-to-many possibility.

Bug: 183993977
Test: refactor, so existing tests pass
Change-Id: Icae8f2128e0ffdf7aee51284cba106963450e3e7
Merged-In: Icae8f2128e0ffdf7aee51284cba106963450e3e7